Wire and device for vascular treatment

ABSTRACT

A wire for use with a vascular treatment device may have a proximal end, a distal end, and a main shaft extending therebetween. The distal end may have a distal free end and a first segment. The first segment may extend from the main shaft and may be biased to a first included angle that is defined between the main shaft and the first segment and less than 180 degrees.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 12/438,314, whichis the National Stage of International application Ser. No.PCT/US2007/078367, filed Sep. 13, 2007, which claims the benefit of U.S.Provisional application Nos. 60/825,529, filed Sep. 13, 2006, and60/916,110, filed May 4, 2007, both of which are hereby incorporatedherein by reference.

SUMMARY

A vascular treatment device may include (1) a handle having a motor, atrigger, and a male coupling, and (2) a cartridge, engageable to thehandle, having a female coupling, a wire, and a sheath fixed to thecartridge. When the female coupling is not engaged to the male coupling,the sheath may cover the distal end of the wire, allowing safeadvancement of the device into the patient's vasculature, and when thefemale coupling is engaged by the male coupling, the distal end of thewire may be exposed from the sheath and used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of an assembly of a vascular treatmentdevice.

FIG. 2 illustrates a longitudinal cross-sectional view of the embodimentillustrated in FIG. 1.

FIG. 3 shows a longitudinal cross-sectional view of a handle.

FIG. 4 illustrates a longitudinal cross-sectional view of a cartridge.

FIG. 5 shows the cartridge illustrated in FIG. 4 with a syringe and astopcock attached.

FIG. 6 shows a perspective view of an embodiment of a vascular treatmentdevice having a single syringe support.

FIG. 7 illustrates an exemplary assembly of the handle of the embodimentdepicted in FIG. 5.

FIG. 8 depicts a top plan view of a portion of the handle illustrated inFIG. 7.

FIGS. 9-10 depict various embodiments of wire distal ends.

FIGS. 11-13 illustrate transverse cross-sectional views of variousembodiments of wire distal tips about which springs are wrapped.

FIGS. 14-14A, 15-15A, 16-16A, 17-17A, 18-18A, 19-19A, 20-20A, 21-21A,22-22A, 23, and 24 depict various embodiments of wire distal ends.

DETAILED DESCRIPTION

A vascular treatment device may be used for ablating blood vessels, suchas varicose veins, and for treating thrombosis by macerating a clot andinjecting a thrombolytic drug, among other uses. A vascular treatmentdevice may include a rotatable wire, so sized and shaped for ablatingblood vessels, coupled to a cartridge that is engageable to a handle.The wire may thus be indirectly engaged with a motor in the handle suchthat the wire rotates when the motor is turned on. When the device isused for treating a varicose vein, the rotating wire may perturb thevessel to cause vasospasm, a condition in which blood vessels spasm, andmay cause damage to the vessel wall to promote sclerosis. During athrombectomy procedure, the wire may macerate a clot without causingdamage to the vessel wall.

FIG. 1 shows an embodiment of an assembly of a vascular treatment device10 having a handle 12 and a cartridge 14. The cartridge 14 may be sosized and shaped to engage to the handle 12 by fitting one component toanother as shown. An embodiment of the handle 12 is shown in greaterdetail in FIG. 3. The handle may define a receptacle 29 in which themale coupling 30 is positioned to receive the female coupling 40 of thecartridge 14 when the cartridge 14 and the handle 12 engage. The handle12 may include a motor 22, a trigger 26, and a male coupling 30. Themale coupling 30 may be connected to the motor 22 in such a way that themotor rotably drives the male coupling upon activation. A potentiometer24 may be electrically coupled to the motor 22 to control a speed of themotor. The trigger 26 may be mounted on the handle and transitionablebetween a first state, which does not couple the motor to a power sourceelectrically, and a second state, which couples the motor to a powersource.

The handle 12 may also include a power source 20 and a microswitch 28connected to the motor 22 by a wire 32. The microswitch 28 may beinterposed in an electrical circuit connecting the trigger 26 and themotor 22. The microswitch may be biased to an open position such thatthe circuit between the trigger and the motor is open. When thecartridge 14 is engaged in the handle 12, the cartridge may pressagainst the microswitch, causing it to transition to a closed state,thereby completing the electrical circuit connecting the trigger 26 andmotor 22. For example, the microswitch may include two contacts with aconductor that is attached to one contact and disconnected from thesecond contact when the microswitch is in an open state. In oneembodiment, the conductor may include a strip of metal that hangs in thechannel into which the cartridge is slid during engagement with thehandle. As the cartridge is engaged in the handle, it pushes the metalstrip out of the channel and into connection with the second contact ofthe microswitch. One advantage gained from such configuration may bethat a user will not be able to activate the device inadvertently bypressing on the trigger before he/she is ready to use the device, i.e.,before the cartridge 14 is fully engaged to the handle 12.

The handle may 12 also include a switch 16 as shown in FIG. 3. Theswitch 16 allows the cartridge 14 to be received by, and secured in, thehandle 12. The switch may include a grip 15 to permit a user to operatethe switch with a finger. The switch may also include a gate 17 thatalternately obstructs or locks the cartridge, depending on the gate'sposition. For example, a user may put a thumb on the grip 15 and pushthe switch 16 away from the handle grip 25 to transition the switch 16from a first position, in which gate 17 is positioned in the channel andso prevents engagement of the cartridge 12 and the handle 14, to asecond position in which gate 17 is moved out of the channel and therebypermits engagement of the cartridge and the handle. Upon release of thebiased switch 16, the gate 17 may fit into a complementary detent in thecartridge and thereby help keep the cartridge engaged with the handle.

The gate 17 may be biased to the first position by a spring 23contacting the handle. As the user pushes the switch 16 away from thehandle grip 25, the switch 16 will push on the spring, thereby creatinga restoring force to urge the switch to its original position once theuser releases the switch.

As noted above, the gate 17 may be further transitionable to a thirdposition which prevents disengagement of the cartridge 14 from thehandle 12. For example, the gate 17 may be forced into the detent 35(shown in FIG. 4), defined by the cartridge 14, when the biased switch16 returns to its original position from the second position to lock thecartridge to the handle.

One or more portions of the handle 12 may define a trigger ring 18 inwhich the trigger is at least partly disposed and about which the handleis so arranged as to be balanced when supported from only one or moreportions of the handle that define the trigger ring. In this manner, auser may balance the handle simply by supporting it with a singlefinger, such as an index finger, against a portion of the handle thatdefines the trigger ring 18. As motor 22 may well be the heaviestcomponent in the handle, it can be positioned below the trigger 26 asshown in FIG. 3 to reduce the bending moment applied by the motor 22 ona finger supporting the handle by the trigger ring, thereby reducingfatigue experienced by the user.

The handle 12 may be formed by joining two outer casing pieces together.

An embodiment of the cartridge 14 shown in FIG. 1 is illustrated ingreater detail in FIG. 4. The cartridge 14 may include a female coupling40, a wire 33 (shown as a broken line), and a sheath 32 fixed to andextending from the cartridge 14. The wire may be fixed to the femalecoupling 40; for example, the wire's proximal tip may be bentapproximately 90 degrees to fit through a channel that is sized andshaped to receive the bent end of the wire. A setscrew may be receivedin the female coupling 40 and/or an appropriate adhesive may be used tosecure the wire and prevent it from rotating with respect to the femalecoupling.

The sheath 32 may define a lumen through which the wire 33 runs. Thesheath 32 may have a wide range of inner and outer diameters. In someembodiments, the sheath may have an inner diameter in the range of from0.022 inches to 0.048 inches. In some embodiments, the sheath 32 mayhave an outer diameter in the range of from 0.025 inches to 0.051inches. The outer diameter of the sheath may also be in the range thatis consistent with the standard needles having corresponding innerdiameters. For example, the sheath may be so sized and shaped to beinsertable in a standard needle or vascular sheath having an innerdiameter in the range of from 0.0035 inches to 0.1060 inches, or from0.0160 inches to 0.0420 inches, or from 0.0420 inches to 0.0630 inches,or from 0.0115 inches to 0.0630 inches. The maximum outer diameter ofthe sheath may be less than 0.035 inches to allow the sheath to beinserted through a intravenous needle or catheter having an innerdiameter of less than 0.0039 inches to allow a wider range ofpractitioners to perform the procedure. Needles, catheters or vascularsheaths with an outer diameter greater than 0.079 inches (6 French, Fr)or 0.092 inches (7 Fr) typically require insertion to be performed by avascular surgeon or interventional radiologist.

The sheath 32 may also include external markings at regular intervalswhich may guide the user to monitor the insertion or removal speed ofthe device 10.

One exemplary embodiment depicting a reservoir connectable to thecartridge may include a syringe 44, a stopcock 46, and a plunger 48 asshown in FIG. 5. The syringe 44 may be in fluid communication with thebore of the sheath 32 for releasing a substance at the wire distal end,such as a sclerosant (examples of which include polidocanol, sodiumtetradecyl sulfate, and hypertonic saline), or thrombolytic drug(examples of which include alteplase (Activase), anistreplase (Eminase),streptokinase (Streptase, Kabikinase), urokinase (Abbokinase), andtissue plasminogen activator (TPA). In this manner, physicalperturbation by the wire may be synergistically combined with drugtreatment to improve device efficacy.

The handle 12 may include a support 19 (shown in FIG. 3) so positionedas to receive the syringe 44. The support 19 may be so sized and shapedto be compatible with the standard syringes and may prevent the syringefrom falling out during injection, especially if the material beinginjected has high volume and/or viscosity and requires significant userthumb pressure upon the syringe. When the cartridge 14 with an attachedsyringe 44 is engaged to the handle, the syringe 44 may snap onto thesupport 19. As shown in FIG. 1, the support may be formed from twobrackets which cradle the syringe. An alternative embodiment shown inFIGS. 6 and 7 includes a support formed from a single hook that wrapspartially around the syringe. These embodiments allow use of the devicewith the right as well as left hand, depending on the user's preferenceand/or the patient's position on the treatment table.

The handle 12 and the syringe 44 may be so sized, shaped, and positionedas to permit a user to actuate the trigger 26 with the index finger of ahand and simultaneously depress a plunger 48 into the syringe with thethumb of the same hand, allowing a treatment drug to be deployed fromthe syringe through the sheath while the wire 33 is rotating. Forexample, a user may hold the handle by positioning the handle grip 25 inthe center of the palm and wrapping third, fourth, and fifth fingeraround the handle grip and putting an index finger through the triggerring 18 and if needed, placing a thumb to depress the plunger to releasetreatment drug into the syringe. The handle may be so designed to allowboth right- and left-handed users to operate.

The stopcock 46 shown in FIG. 5 may allow reloading of fluid and alsochanging the fluid concentration of composition as well as mixing of thesclerosant fluid with gas. For example, air can be mixed for generatingfoam as well as agitating existing sclerosant/gas mixture and alsorecreating the foam, because the foam has a limited duration (typicallya minute or less) before the fluid and gas start to separate. Thestopcock 46 may allow the fluid composition mixture to be agitatedwithout disconnecting the syringe from the cartridge or without stoppingthe procedure.

A standard Y hemostasis connector 34 as shown in FIG. 4, or other Yhemostasis connector, may be used to aid in fluid communication betweenthe syringe 44 and the lumen defined by the sheath 32. A Y-hemostasisconnector 34 may be connected to the female luer hub 31 and to thetubing nut 36 to prevent the fluid from leaking into the regioncontaining the motor 22. An O-ring may be used to prevent leaks aroundthe wire shaft. Wire tubing 42 may be so sized and shaped to receive thewire 33 and attached to the female coupling 40. Combining the abovementioned components may allow the motor to rotate the wire withoutincreasing the torque beyond the appropriate working range. The motormay spin in the range of from 500 to 3000 rpm-4000 rpm for varicose veindestruction and thrombectomy procedures. The handle may also include abuilt-in RPM display for user to read the speed or may include anelectrical port through which the speed may measured by an externalmonitor.

The male coupling 30 on the handle 12 may be biased toward an expandedstate and transitionable from the expanded state to a contracted state.The female coupling 40 may be so sized and shaped as to transition themale coupling 30 from the expanded state to the contracted state duringengagement of the handle 12 and the cartridge 14. As the male coupling30 and the female coupling 40 fully engage each other, the male couplingdisplaces the female coupling detents to allow the female coupling toslide within the cartridge.

Attaching the female coupling 40 to the male coupling 30 thereby causesthe sheath 32 to slide back relative to the wire. This occurs becausethe sheath is fixed to the cartridge, while the wire is fixed to thefemale coupling. As the cartridge is fully seated in the handle, thefemale coupling is pushed forward in the cartridge. So when the femalecoupling 40 is not engaged by the male coupling 30, the sheath 32 maycover the distal end of the wire 33, allowing it to be safely advancedin the patient's vasculature; and when the female coupling 40 is engagedby the male coupling 30, the sheath may reveal the distal end of thewire. Consequently, when the female and male couplings are engaged thedistal tip of the wire is revealed, and (2) the wire is operably coupledto the motor 22 through the female and male couplings, to allow themotor to rotate the wire 33. As noted above, the cartridge may also tripa lever arm coupled to the microswitch 28 to complete a circuit betweenthe trigger 26 and the motor 22. The male coupling 30 may be so sizedand shaped as to return to the expanded state once the cartridge 14 andthe handle 12 are fully engaged as described earlier.

The female coupling may be disengaged from the male coupling to re-coverthe distal tip of the wire when the wire is to be removed for the siteof use, or if a treatment is interrupted. Disengaging the femalecoupling from the male coupling slides the wire 33 with respect to thesheath 32 (attached to the cartridge fixed to the handle); as a resultthe tip of the wire is no longer exposed, allowing it to be safelyremoved. This mechanism may protect the tip of the wire 33 prior to useand also protect the blood vessels and other body tissues during removalor repositioning of the device.

The male coupling 30 may have at least two prongs separated by slittedportions to facilitate the transition from the expanded state to thecontracted state. The male coupling may be made with polycarbonate,plastic, or other materials which allow transitioning between anexpanded state to a contracted state.

In some embodiments, the vascular treatment device 10 may be of a singlepiece construct having a handle and a cartridge. The cartridge may beassembled to the handle during manufacturing and be able to transitionwithin the handle between a first position, where the male and femalecouplings are not engaged, and a second position, where the male andfemale couplings are engaged. An embodiment of such device may allow thecartridge to slide back and forth within a predetermined range, such asthe first and the second position, in the groove defined by the handle,but the cartridge may not disengage itself from the handle. A sheath maybe fixed and extend from the cartridge and define a lumen through whichthe wire runs. The cartridge may also include a syringe to be receivedby a support mounted on the handle.

In this embodiment, the handle may include a motor, a motor coupling, atrigger, and a power source. The wire having a main shaft, a distal end,and a proximal end which is fixed to the motor coupling may be attachedto the motor coupling. The motor coupling may be rotably driven by themotor. The trigger may be mounted on the handle and be transitionablebetween a first state, which does not couple the motor to a power sourceelectrically, and a second state, which couples the motor to a powersource. The handle may also include a microswitch to permit trigger andthe motor to be electrically coupled to one another.

At the first position, the cartridge may cover the distal tip of thewire. At the second position, the cartridge (1) exposes the distal tipof the wire from the sheath, and (2) completes a circuit between thetrigger and the motor by tripping a lever arm coupled to themicroswitch. Therefore, the single piece construct vascular treatmentdevice may allow a user to obtain similar functionality as the deviceexplained earlier and shown in FIG. 1.

FIG. 6 illustrates another embodiment of vascular treatment device 10.The handle may have a support 19 for the syringe 46 in the form of ahook, as described above. This embodiment may be assembled by mating twocasings as shown in FIG. 7. The syringe may snap onto the support andremain in position during the use of the device. The support 19 (and/orhandle 12) may be made of SLA resin or other materials that would allowthe support to withstand the snapping force applied by the syringe.

FIG. 8 shows a top view of the end of an alternate embodiment of handle12 having a notch 80 for retaining the cartridge 14 (not shown) to thehandle 12. In the previously mentioned embodiments, the handle had aswitch that may be coupled to a gate which held the cartridge to thehandle. In this configuration, the notch 80 may prevent the cartridgefrom disengaging from the handle. In use, a user may slide the cartridgeinto the handle and then “cock” the cartridge into notch 80 to preventthe cartridge from slipping out of the handle.

A wide variety of distal wire tips may be used; FIGS. 9-11, 14-14A,15-15A, 16-16A, 17-17A, 18-18A, 19-19A, 20-20A, 21-21A, 22-22A, 23, and24 show several examples.

FIG. 9 shows an embodiment of a wire 33 having a proximal end 50, adistal end 52 and in proximal-to-distal order, a first segment 54, asecond segment 56, and a third segment 58. The first segment 54 mayextend between the main shaft 51 and the second segment 56 and may bebiased to a first included angle α that is defined between the mainshaft 51 and the first segment 54 and is less than 180 degrees. Thesecond segment 56 may extend between the first segment 54 and the thirdsegment 58 and may be biased to a second included angle β that isdefined between the first segment 54 and the second segment 56 and isless than 180 degrees. The third segment 58 may extend from the secondsegment 56 to a free end and may be biased to a third included angle γthat is defined between the second segment 56 and the third segment 58and is less than 180 degrees.

The second included angle may be greater than the first included angle.The sum of the first included angle and the third included angle, minusthe second included angle, may be in the range of about 70 degrees toabout 110 degrees. The sum of the first included angle and the thirdincluded angle, minus the second included angle may be in the rangeabout 80 degrees to about 100 degrees. The sum of the first includedangle and the third included angle, minus the second included angle maybe about 90 degrees.

The third segment 58 of the wire 33 may have a length that is smallerthan the inner diameter of the sheath 32. For example, the third segment58 may have a length of less than 0.028 inches or it may have a lengththat is equal to or smaller than two-thirds of the inner diameter of thesheath 32.

The perpendicular distance measured from an center axis of the mainshaft 51 to the free end may be less than 0.3 inches. The first segment54 and the second segment 56 each may have a length in the range ofabout 0.2 inches to about 0.3 inches, or in the range about 0.24 inchesto about 0.26 inches. The length of the first segment 54 may be in therange of about 0.248 inches to about 0.25 inches, and the length of thesecond segment is in the range of about 0.25 inches to about 0.252inches. In one embodiment, the length of the first segment 54 may be0.249 inches, and the length of the second segment is 0.2504 inches.

The distal end 52 of the wire 33 may include at least two linearsegments oriented at a non-zero angle relative to one another. Having atleast two linear segments may allow the distal tip of the wire to tuckinto a sheath without touching the wall of the sheath, and it may alsoallow the main shaft of the wire to run along the vessel wall while thetip (for example, the third segment) of the wire digs into the vesselwall.

The wire tip located on the distal end 52 may have a wide variety ofconfigurations, depending on the intended use. The wire shape may be“atraumatic,” meaning that it may be shaped such that insertion causeslittle or no spasm or damage to the vessel. For example, FIG. 10 shows adistal end 52 terminating with a hemispheric free end. The hemisphericend may be textured or mechanically or chemically altered to create aroughened surface. Other atraumatic tips may include an end having afull radius, or a J-curved shape, or simply a curved shape.

FIG. 10 shows an atraumatic tip having a sleeve extending from thehemispheric shape along the wire 33 towards the proximal end of thewire. The sleeve 70 can add strength to the distal tip, therebyincreasing the scrapping force and increasing the contact surface areato prevent detachment of the hemispheric tip 72.

In other embodiments, the distal tip 52 may be “aggressive” and be bentor curved so that it scrapes the vessel wall. FIG. 9 shows the distalend 52 having a flat free end with a sharp edge around. An aggressivedistal tip 52 may also be created by beveling an edge to create a sharppoint. The distal tip having a cutting blade, like a shark's fin, mayalso be aggressive. The distal tip 52 may be roughened to make thedistal tip cut more aggressively and/or cause spasm to the blood vesselwall.

A roughened surface may be formed by subjecting an initially smoothsteel to abrasion, machining, blasting, chemical etching such as acidetching (for example, nitric acid, hydrofluoric acid, hydrochloric acid,and/or sulfuric acid). A roughened outer surface may also be created byrolling a sheet metal, such as a sheet forming the sleeve 70, onto anirregularly shaped guide to create surface irregularity.

Also, the outer surfaces of the first, the second, and/or the thirdsegments may be coated with an abrasive to roughen the surface. Othersurface treatments may include a bastard cut file type or diamond grit.For example, 30 grit diamond may produce an aggressive surface and 200grit diamond may produce a non-aggressive surface.

During use, especially with a roughened tip, the wire may beperiodically re-encased in the sheath to help dislodge debris from thewire tip and keep the device operating normally.

An aggressive surface may also be formed on the first segment 54 and/orthe second segments 56 of the wire 33 by introducing a screw threadedprofile with a second wire along the length of the wire 33 by followinga screw flights of various shapes such as a square, or a rhomboid, or atrapezoid, or a parallelogram, or an ellipse, or a triangle, or apentagon.

FIG. 10 shows an embodiment having a first segment 56 with a sleeve 70having a roughened outer surface using one of various methods mentionedearlier. In addition to showing a roughened surface treatment, FIG. 10further illustrates a wire with a weight added at the distal tip, inthis case the weight is added by a sleeve with a roughed outer surface.The weight may be centered on the wire or eccentrically positioned. Aneccentric weight may cause the wire to flail about during rotation. Theflailing may perturb the vessels more aggressively compared to a wirewith centrically added weight.

The distal end 52 of the wire 33 may also include a curved segment. Thecurvature of the curved segment may be constant, or it may follow othercurves, such as a sector of an ellipse or an oval. The distal end 52 ofthe wire 33 may also have a straight segment distal to the curvedsegment. Similar to the embodiments with a constant curvature, thecurvature of the curved section with a straight segment may be constantor it may follow previously mentioned shapes.

A spring 90 may be attached from the distal end 52 of the wire 33 alongthe first segment 54 and/or the second segment 56 to create anaggressive cutting surface. The ends of the spring may be brazed atmultiple points. The spring 90 may follow the various profiles mentionedearlier. FIGS. 11-13 illustrate cross-sectional views of a springfollowing screw flights of a square, a trapezoid, and a pentagon,respectively.

The sharp corners of the various profiles (for example, a square, atriangle, a parallelogram, a pentagon) may dig into the blood vesselwall and ablate the vessel wall. The wire 33 may have a hemispheric or aflat free end depending on the intended use. The hemispheric end or flatfree end may also be textured or roughened.

FIGS. 14-14A show a wire similar to that shown in FIG. 9 having first,second, and third linear segments distal to the main shaft.

FIGS. 15-15A show a wire similar to that shown in FIGS. 14-14A, in whichthe free end of the third segment is hemispherical.

FIGS. 16-16A show a wire having a curved segment distal to the mainshaft, and in which the free end of the curved segment is hemispherical.

FIGS. 17-17A show a wire similar to that shown in FIG. 10 having first,second, and third linear segments, with weight added at the distal tip.

FIGS. 18-18A show a wire having a single linear segment distal to themain shaft, in which the linear segment terminates with a ball-shapedfree end.

FIGS. 19-19A show a wire having a single linear segment distal to themain shaft, in which the distal tip has added weight and the free end ishemispherical.

FIGS. 20-20A show a wire having two linear segments distal to the mainshaft, in which the second linear segment terminates with a ball-shapedfree end.

FIGS. 21-21A show a wire having two linear segments distal to the mainshaft, in which the second linear segment has added weight andterminates with hemispherical free end.

FIGS. 22-22A show a wire similar to that shown in FIGS. 14-14A, havingthree linear segments in which the third segment terminates with a sharpfree end.

FIGS. 23-24 show wires having a spring wrapped around the distal portionof the wire.

We claim:
 1. A wire for use with a vascular treatment device, the wirecomprising a proximal end, a distal end, and a main shaft extendingtherebetween; wherein: the distal end comprises a distal free end and afirst segment; the first segment extends from the main shaft; and thefirst segment is biased to a first included angle that is: definedbetween the main shaft and the first segment; and less than 180 degrees.2. The wire of claim 1, wherein the distal free end is ball-shaped. 3.The wire of claim 2, wherein the first segment extends from the mainshaft to the distal free end.
 4. The wire of claim 1, wherein the distalend further comprises a second segment and a third segment, wherein: thesecond segment extends between the first segment and the third segmentand is biased to a second included angle that is: defined between thefirst segment and the second segment; and is less than 180 degrees; andthe third segment extends from the second segment to the free end and isbiased to a third included angle that is: defined between the secondsegment and the third segment; and is less than 180 degrees.
 5. The wireof claim 4, wherein the second included angle is greater than the firstincluded angle.
 6. The wire of claim 4, wherein the sum of the firstincluded angle and the third included angle, minus the second includedangle, is in the range of about 70 degrees to about 110 degrees.
 7. Thewire of claim 6, wherein the sum of the first included angle and thethird included angle, minus the second included angle, is in the rangeof about 80 degrees to about 100 degrees.
 8. The wire of claim 7,wherein the sum of the first included angle and the third includedangle, minus the second included angle, is about 90 degrees.
 9. The wireof claim 4, wherein the third segment has a length that is smaller thanan inner diameter of the sheath.
 10. The wire of claim 9, wherein thethird segment has a length of less than 0.028 inches.
 11. The wire ofclaim 9, wherein the third segment has a length that is equal to orsmaller than two-thirds of the inner diameter of the sheath.
 12. Thewire of claim 4, wherein the first and second segments each have alength in the range of about 0.2 inches to about 0.3 inches.
 13. Thewire of claim 12, wherein the first and second segments each havelengths in range of about 0.24 inches to about 0.26 inches.
 14. The wireof claim 30, wherein the length of the first segment is in the range ofabout 0.248 inches to about 0.25 inches, and the length of the secondsegment is in the range of about 0.25 inches to about 0.252 inches. 15.The wire of claim 14, wherein the length of the first segment is 0.249inches, and the length of the second segment is 0.2504 inches.
 16. Thewire of claim 1, wherein the distal end has at least two linear segmentsoriented at a non-zero angle relative to one another.
 17. The wire ofclaim 1, wherein the distal free end is ball-shaped, the first segmentextends from the main shaft to the distal free end, and the firstincluded angle is 140 degrees.
 18. The wire of claim 1, wherein thedistal free end is textured.
 19. The wire of claim 1, wherein the distalfree end is pointed.
 20. The wire of claim 1, wherein the distal freeend is flat.
 21. The wire of claim 1, wherein the distal end isweighted.
 22. The wire of claim 21, wherein the distal end iseccentrically weighted relative to the main shaft.
 23. The wire of claim1, wherein the distal end has a roughened surface.
 24. The wire of claim1, wherein the wire further comprises a spring attached along the distalend.
 25. The wire of claim 1, wherein the wire distal end comprises acurved segment.
 26. The wire of claim 25, wherein the wire distal endcomprises a straight segment distal to the curved segment.
 27. The wireof claim 1, wherein a perpendicular length measured from an axis definedby the main shaft to the free end is less than 0.3 inches.
 28. Avascular treatment device comprising: a handle having: a motor; atrigger mounted on the handle and transitionable between a first statethat does not electrically couple the motor to a power source and asecond state that does couple the motor to the power source; and a malecoupling rotably driven by the motor; and a cartridge engageable withthe handle and having: a female coupling so sized and shaped as to beengageable by, and once engaged by, to be rotated by the male coupling;the wire of claim 1, wherein the wire proximal end is fixed to thefemale coupling; and a sheath fixed to and extending from the cartridge,the sheath defining a lumen through which the wire runs; wherein thesheath, when the female coupling is not engaged by the male coupling,covers the distal end of the wire, and wherein the sheath, when thefemale coupling is engaged by the male coupling, does not cover thedistal end of the wire.
 29. The device of claim 28, wherein the systemcomprises a gate that is biased to a first position that preventsengagement of the cartridge and the handle and is transitionable to asecond position that permits engagement of the cartridge and the handle.30. The device of claim 29, wherein the gate is further transitionableto a third position that prevents disengagement of the cartridge and thehandle.
 31. The device of claim 30, wherein the third position isintermediate the first and second positions.
 32. The device of claim 30,wherein the gate, when in the third position, is received in a detentdefined in the cartridge.
 33. The device of claim 29, wherein the gateis biased to the first position by a spring contacting the handle. 34.The device of claim 29, wherein the gate is physically coupled to aswitch on the handle such that movement of the switch transitions thegate between the first position and the second position.
 35. The deviceof claim 28, wherein the handle includes a potentiometer electricallycoupled to the motor to control a speed of the motor.
 36. The device ofclaim 28, wherein the male coupling is biased toward an expanded stateand transitionable from the expanded state to a contracted state. 37.The device of claim 36, wherein the female coupling is so sized andshaped as to transition the male coupling from the expanded state to thecontracted state during engagement of the handle and the cartridge. 38.The device of claim 36, wherein the male coupling is so sized and shapedas to return to the expanded state once the cartridge and the handle arefully engaged.
 39. The device of claim 38, wherein the female couplingis disengageable from the male coupling once the male coupling hasreturned to the expanded state.
 40. The device of claim 38, wherein thefemale coupling is not disengageable from the male coupling once themale coupling has returned to the expanded state.
 41. The device ofclaim 36, wherein the male coupling comprises at least two prongsseparated by slitted portions.
 42. The device of claim 28, wherein thesheath has an inner diameter between 0.022 inches to 0.048 inches. 43.The device of claim 28, wherein the sheath has an outer diameter between0.020 inches to 0.050 inches to facilitate insertion into a vein. 44.The device of claim 28, wherein one or more portions of the handledefine a trigger ring in which the trigger is at least partly disposed,and wherein the handle is so arranged as to be balanced when supportedfrom only one or more portions of the handle that define the triggerring.
 45. The device of claim 28, wherein the sheath comprises externalmarkings at regular intervals.
 46. The device of claim 28, furthercomprising a microswitch interposed in an electrical circuit connectingthe trigger and the motor and transitionable by engagement of thecartridge and the handle from an open state to a closed state, therebypermitting the trigger and motor to be electrically coupled to oneanother.
 47. The device of claim 28, wherein the handle: comprises acasing formed from two pieces; contains the motor and the male coupling;and defines a receptacle in which the male coupling is positioned andwhich receives the female coupling of the cartridge when the cartridgeand the handle engage.
 48. The device of claim 28, further comprising asyringe in fluid communication with the sheath lumen.
 49. The device ofclaim 48, wherein the syringe is attached to the cartridge.
 50. Thedevice of claim 48, wherein the syringe is attachable to the cartridgewith or without a stopcock.
 51. The device of claim 48, wherein thehandle further comprises a support so positioned as to receive thesyringe.
 52. The device of claim 48, wherein the handle and the syringeare so sized, shaped, and positioned as to permit a user to actuate thetrigger with the index finger of a hand and simultaneously depress aplunger into the syringe with the thumb of the same hand.